In the United States, one "standard" drink contains 0.6 fluid ounces of pure alcohol. These drinks are different sizes, but they all count as one standard drink:

12 ounces of beer (5% alcohol by volume)

4-5 ounces of wine (12% alcohol by volume)

1.5 ounces of 80-proof hard liquor (40% alcohol by volume)

Alcohol content can vary widely, so it's important to check the label when you're drinking something new. A 151-proof bottle of spirits, for example, is 75% alcohol by volume. Most alcohol containers list the alcohol content on the package.